Force feedback is used primarily with position control systems wherein a force presented at an input control corresponds with the position of an actuated output. In these systems the forces adjacent to an endpoint on the arm being controlled are determined or sensed and corresponding scaled forces are applied to the input control to provide the operator with a tactile simulation of the forces on the endpoint based on the scaled forces which the operator works against to move the input control in order to position the actuated output at a desired position.
There are various methods to provide this tactile feedback and they are broadly classified as passive methods or active methods. Passive methods use passive mechanical components such as springs and dampers to generate the feedback forces. Active methods use an electric motor, electronics and software to generate the feedback forces.
Active methods, however, can be costly to implement. This is because the components of this system have to be very high quality to generate a force signal that is free of noise and other disturbances. Existing methods usually employ force sensors, precision gear-trains, electronic components of high accuracy, and a high bandwidth force control loop implemented in software. Additionally, for reasons of reliability and availability, the designer may be required to implement a minimum of a dual redundant system. These factors contribute to increasing the cost of the system.